Oil and other cargo can be transferred between an undersea pipeline (connected to undersea wells or a shore-based installation) and a tanker or other vessel, by the use of a single point mooring and cargo transfer system. Such a system can include a transfer structure, which may include a buoy anchored to the sea floor through several loose chains, or which may include a tower extending up from the sea floor to above the sea surface. A hawser can connect the transfer structure (buoy or tower) to the vessel, while a floating hose can extend from a fluid swivel on the transfer structure to the vessel to transfer a cargo such as oil between them. The use of a floating hose to transfer fluid from a transfer structure to a vessel is undesirable in many cases. For example, where LNG (liquified natural gas) is to be transferred, it is difficult to provide a flexible hose that can lie in the water, and which will have a reliable long lifetime. Even in the transference of oil, a floating hose structure is an expensive and high maintenance item.
The transference of fluid cargo between a transfer structure and a vessel can be effected by the use of a boom to support a rigid pipe or even a flexible hose above the water. However, the coupling of the end of a boom to a vessel is a delicate task, especially in areas of rough seas. A boom which could be connected to a vessel in a relatively short time, with minimal possibility of damage to the boom, and wherein the boom could resist damage in stormy weather when not connected to a vessel, would be of great value in the transport of hydrocarbons.